From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FFF6CA9ECB for ; Thu, 31 Oct 2019 18:43:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 776CF20873 for ; Thu, 31 Oct 2019 18:43:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572547432; bh=fdAfMNAe36f/3COL7qXnHCukzReyQ3PyEAz9/OgiPSA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=WCL9kQvfYR7Fc6MC/FqYouothP8Z8y/8CWVSKyG6foYv5kyt7aUqagWxpxsWLotl8 Cr7BbLqP47oR15VDTK8RJcIdOuyoMVOCy/pGbhRYDmdyWA0j16adljoXyWI0dqpsIv Va+57jfKymQ/TrG3HmPn2KwVlVdAAdd0cMLd0HPE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729494AbfJaSnv (ORCPT ); Thu, 31 Oct 2019 14:43:51 -0400 Received: from mail-qt1-f196.google.com ([209.85.160.196]:35972 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729304AbfJaSnu (ORCPT ); Thu, 31 Oct 2019 14:43:50 -0400 Received: by mail-qt1-f196.google.com with SMTP id y10so3111270qto.3; Thu, 31 Oct 2019 11:43:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Hfo2/9DpljbvAhB9xl0YdOSI7Py9wSatQChmRyBaX2Y=; b=peHYAPeXlBqrPFee2+Ck4DPkyTNSAkZMt4NL2IB8D3i6SnLsaxm94Z8WT/Pkw5KEmn XQGCo7nu0OykrB+FvY75HEtIXp5NbHuSrunM4BeNeexfSauFgmGxUac2SHFknPFaE+i1 vgQykTq0ATqdXnzwYyjinkYHm4bQvCo0KweOcK7sssmUK0rdQPBeFyebfxchH516hZ4h mkwcw3jbcwKYtyE7sSGzNcfEGhx34OqVuepXFnzOgV4AJfHsdWfDE+y8la5+R9D0wD0H ETxkg/gZeIaGqkAPuzTN9tqQitF72e8cRAgYe0QnO//swqQLt5dWnEceAKrcGgXsvX1i 8Ulw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=Hfo2/9DpljbvAhB9xl0YdOSI7Py9wSatQChmRyBaX2Y=; b=he2kzJvdQ8QTWV3K8RK9G2N/YFQar6mqKEDjOamCLZbtFTvC0wVasS4nLt5Cd/FpPu EV/ZMJjn8kL/Vz9CWKJ+YzOFOzk8Ps+nlSF+wJ1pDDtc2NWQJnkdFC3G+OynzbILx4Rh 1lvj6qGAYSAnvE0v+OCIsMM9v2BUuGNHcjwuQ0g1PZwflAzVbQuk/M/Gkohdpiy2KYXr Z9kw4eyt6sHrIs7HDfZhxL+vMTDaN/XB318RASlh+UvabzIpDd2e1MpC7P26YLRFV2xU xV2qjDdUWn8kPntF5bPNJaUqkbYce9IUGMWPeXmkqFoVFarbq84/CqLnUvql3UU69lVe 4S2Q== X-Gm-Message-State: APjAAAXfa5oYzkuwgdgoSHn3ofiv28mZYUW8UQEAeGSUUu/qFGhsZXrr uMP0zJWC8we71V2ww1uN+Gs= X-Google-Smtp-Source: APXvYqySb6tIznbjqfsQ8WMDhIHY8G3NjOyExytgE1RmUg4EJoBT2Wq/6z6BRRe1QvcVE4Trsj5QDw== X-Received: by 2002:ac8:866:: with SMTP id x35mr6771728qth.90.1572547428789; Thu, 31 Oct 2019 11:43:48 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::e44c]) by smtp.gmail.com with ESMTPSA id i75sm2451492qke.22.2019.10.31.11.43.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Oct 2019 11:43:48 -0700 (PDT) Date: Thu, 31 Oct 2019 11:43:46 -0700 From: Tejun Heo To: Shakeel Butt Cc: Eric Dumazet , Michal Hocko , "David S. Miller" , netdev@vger.kernel.org, Kernel Team , LKML , Josef Bacik , Jakub Kicinski , Johannes Weiner , Linux MM , Mel Gorman , Andrew Morton Subject: Re: [PATCH v2] net: fix sk_page_frag() recursion from memory reclaim Message-ID: <20191031184346.GM3622521@devbig004.ftw2.facebook.com> References: <20191019170141.GQ18794@devbig004.ftw2.facebook.com> <20191024205027.GF3622521@devbig004.ftw2.facebook.com> <11f688a6-0288-0ec4-f925-7b8f16ec011b@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Thu, Oct 31, 2019 at 11:30:57AM -0700, Shakeel Butt wrote: > Basically what I wanted to say that MM treats PF_MEMALLOC as the > reclaim context while __GFP_MEMALLOC just tells to give access to the > reserves. As gfpflags_allow_blocking() can be used beyond net > subsystem, my only concern is its potential usage under PF_MEMALLOC > context but without __GFP_MEMALLOC. Yeah, PF_MEMALLOC is likely the better condition to check here as we primarily want to know whether %current might be recursing and that should be indicated reliably with PF_MEMALLOC. Wanna prep a patch for it? Thanks. -- tejun